Subject: [ASA-202011-19] libass: arbitrary code execution

Arch Linux Security Advisory ASA-202011-19
==========================================

Severity: Medium
Date    : 2020-11-19
CVE-ID  : CVE-2020-26682
Package : libass
Type    : arbitrary code execution
Remote  : No
Link    : https://security.archlinux.org/AVG-1285

Summary
=======

The package libass before version 0.15.0-1 is vulnerable to arbitrary
code execution.

Resolution
==========

Upgrade to 0.15.0-1.

# pacman -Syu "libass>=0.15.0-1"

The problem has been fixed upstream in version 0.15.0.

Workaround
==========

None.

Description
===========

In libass 0.14.0, the ass_outline_construct's call to outline_stroke
causes a signed integer overflow.

Impact
======

A maliciously crafted file might crash the application or execute
arbitrary code.

References
==========

https://github.com/libass/libass/issues/431
https://github.com/libass/libass/pull/432
https://github.com/libass/libass/commit/676f9dc5b52ef406c5527bdadbcb947f11392929
https://security.archlinux.org/CVE-2020-26682